title: Magnetic properties of S = 1/2 quasi-triangular lattice materials: Cu(2(1-x))Zn(2x)(OH)3NO3/(C7H15COO)·mH2O.
abstract: We have investigated the structural and magnetic properties of two classes of spin S = 1/2 antiferromagnetic quasi-triangular lattice materials: Cu(2(1-x))Zn(2x)(OH)(3)NO(3) (0 ≤ x ≤ 0.65) and its long chain organic derivatives Cu(2(1-x))Zn(2x)(OH)(3)(C(7)H(15)COO)·mH(2)O (0 ≤ x ≤ 0.29). The series of layered structure compounds constitute a substitutional magnetic system, in which spin S = 1/2Cu(2+) ions and nonmagnetic Zn(2+) ions are arranged on a two-dimensional quasi-triangular lattice. For the nitrate compounds we found that the substitution of Zn(2+) ions can continuously decrease the Néel temperature, T(N), but never completely remove the magnetic order. In addition, the frustration effect in these materials is suppressed by a three-dimensional interlayer interaction. On the other hand, the corresponding long chain alkyl carboxylic acid group of intercalated materials, Cu(2(1-x))Zn(2x)(OH)(3)(C(7)H(15)COO)·mH(2)O, show spin-glass-like behavior, which is caused by the interplay of geometric frustration and mixed sign interactions. A tentative explanation for these findings is proposed in terms of a cluster-glass picture.
authors.affiliation: Department of Physics and Center for Materials Innovation, Washington University in St Louis, 1 Brookings Drive, St Louis, MO 63130, USA.
authors.forename: J
authors.initials: J
authors.lastname: Wu
authors.forename: A K
authors.initials: AK
authors.lastname: Gangopadhyay
authors.forename: P
authors.initials: P
authors.lastname: Kanjanaboos
authors.forename: S A
authors.initials: SA
authors.lastname: Solin
mesh_terms: D046911:Macromolecular Substances / Q000737:chemistry; D008280:Magnetics; D008422:Materials Testing; D008968:Molecular Conformation; D049329:Nanostructures / Q000737:chemistry* / Q000648:ultrastructure*; D009930:Organic Chemicals / Q000737:chemistry*; D010316:Particle Size; D013499:Surface Properties
chemical_list: D046911:Macromolecular Substances; D009930:Organic Chemicals